Shaped coils for transcranial magnetic stimulation

ABSTRACT

Described herein are shaped coil TMS electromagnets formed by two bent magnetic coil loops joined at a vertex having an angle between the outer coil regions of the coils that is typically less than 120 degrees (e.g., between about 45 and about 70 degrees, 60 degrees, etc.). The vertex region shaped to optimize the magnetic field projected from the TMS electromagnet. For example, the vertex region may be horizontal or vertical. In some variations the vertex region is formed by re-arranging the conductive windings forming the two coils so that they are no longer arranged in the same columnar structure that they are in the other portions of the bent magnetic coil loops. These TMS electromagnets may be well suited for use in deep-brain Transcranial Magnetic Stimulation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/141,100, filed on Aug. 1, 2011, titled “SHAPED COILS FOR TRANSCRANIALMAGNETIC STIMULATION,” now U.S. Patent Application Publication No.2011/0273251, which is a 371 National Phase Application of InternationalPatent Application No. PCT/US2010/020324, filed on Jan. 7, 2010, titled“SHAPED COILS FOR TRANSCRANIAL MAGNETIC STIMULATION,” and published asWO 2010/080879, which claims the benefit of U.S. Provisional PatentApplication No. 61/143,103, filed on Jan. 7, 2009 and titled “SHAPEDCOILS FOR TRANSCRANIAL MAGNETIC STIMULATION,” each of which is hereinincorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

FIELD

The devices and methods described herein relate generally to thefocusing of magnetic fields generated by electromagnets used forTranscranial Magnetic Stimulation (TMS). In particular, shaped coilpairs that are advantageous for TMS are described.

BACKGROUND

A typical Transcranial Magnetic Stimulation (TMS) electromagnet includesa pair of coils that are joined to form a flat figure-8 shapedelectromagnet. Such figure-eight double coil magnets are well known, forinstance the 70 mm double-coil configuration from Magstim (e.g., Model9925, Magstim Ltd., Wales, UK). The electromagnets can be powered bycommercially available power sources such as the “Magstim Rapid²”(Magstim Ltd., Wales, UK) that provides electrical currents for pulsedmagnetic fields. The magnetic field projected from standard figure-8shaped double coil electromagnets is not optimal for deep brainstimulation, however. In particular, the depth and shape of the emittedfield is limited.

For conventional circular and double circular coils, the Biot-Savart lawdictates that magnetic field strength declines as a function of distancefrom face of a coil. This makes focal stimulation of the brainchallenging to achieve at the cortical surface (beneath scalp, skull andmeninges), and even more difficult beneath the cortical surface.

Alternative configurations for TMS electromagnets have been proposed,including those described in Zangen et al. (U.S. Patent applicationspublication Nos. 2006/0287566 and 2004/0078056). Alternative designshave likewise been proposed in Levkovitz Y, Roth Y, Harel E V, Braw Y,Sheer A, Zangen A, “A randomized controlled feasibility and safety studyof deep transcranial magnetic stimulation.” Clin. Neurophysiol.118(12):2730-44 (December 2007).

However, the proposed designs described above each have substantialdisadvantages, particularly with regard to the specificity and controlof the magnetic field generated, as well as the ease with which thesemagnets may be fabricated and characterized.

Described herein are TMS electromagnets configured to address many ofthe problems described above. In particular, the inventors have foundthat, unexpectedly, TMS electromagnets formed from coils that are notlinear, but are instead curved or bent to form a “V”, “U” or “Y” mayresult in magnetic field intensities that are well suited for deep-brainTMS.

The coils described herein for TMS may therefore be designed toaccommodate a difficult balance between focality, and power leveldelivered to a target. This balance has been particularly difficult toachieve with known TMS electromagnets, yet is of great importance whenthe target is below the cortical surface of the brain.

Examples of systems, devices and methods that may benefit from the TMScoils described herein may be found, for example, in any of thefollowing applications: Patent Application No. PCT/US2008/071663,(titled “DEVICE AND METHOD FOR TREATING HYPERTENSION VIA NON-INVASIVENEUROMODULATION”) filed Jul. 30, 2008; Patent Application No.PCT/US2008/072930, (titled “GANTRY AND SWITCHES FOR POSITION-BASEDTRIGGERING OF TMS PULSES IN MOVING COILS”) filed Aug. 12, 2008; PatentApplication No. PCT/US2008/073751, (titled “FIRING PATTERNS FOR DEEPBRAIN TRANSCRANIAL MAGNETIC STIMULATION”), filed Aug. 20, 2008; PatentApplication No. PCT/US2008/075575 (titled “FOCUSING MAGNETIC FIELDS WITHATTRACTOR MAGNETS AND CONCENTRATOR DEVICES”), filed Sep. 8, 2008; PatentApplication No. PCT/US2008/075583 (titled “PITCH, ROLL, AND YAW MOTIONSFOR ELECTROMAGNET ARRAYS”), filed Sep. 8, 2008; Patent Application No.PCT/US2008/075706 (titled “FOCUSED MAGNETIC FIELDS”), filed Sep. 9,2008; Patent Application No. PCT/US2008/075824 (titled “AUTOMATEDMOVEMENT OF ELECTROMAGNETS TRACKING ECCENTRICITY OF THE HEAD”), filedSep. 10, 2008; Patent Application No. PCT/US2008/077851 (titled “SYSTEMSAND METHODS FOR COOLING ELECTROMAGNETS FOR TRANSCRANIAL MAGNETICSTIMULATION”), filed Sep. 26, 2008; Patent Application No.PCT/US2008/079378 (titled “DISPLAY OF MODELED MAGNETIC FIELDS”), filedOct. 9, 2008; Patent Application No. PCT/US2008/081048 (titled“INTRA-SESSION CONTROL OF TRANSCRANIAL MAGNETIC STIMULATION”), filedOct. 24, 2008; Patent Application No. PCT/US2008/081307 (titled“TRANSCRANIAL MAGNETIC STIMULATION WITH PROTECTION OF MAGNET-ADJACENTSTRUCTURES”), filed Oct. 27, 2008; U.S. patent application Ser. No.12/324,227 (titled “TRANSCRANIAL MAGNETIC STIMULATION OF DEEP BRAINTARGETS”), filed Nov. 26, 2008; U.S. patent application Ser. No.12/185,544 (titled “MONOPHASIC MULTI-COIL ARRAYS FOR TRANCRANIALMAGNETIC STIMULATION”), filed Aug. 4, 2008; and Patent Application No.PCT/US2008/072154 (titled “MONOPHASIC MULTI-COIL ARRAYS FOR TRANSCRANIALMAGNETIC STIMULATION”), filed Aug. 4, 2008.

SUMMARY OF THE DISCLOSURE

The present invention provides an improved design for magnetic brainstimulation coils. This coil design (generally referred to as a“V-shaped coil”) may yield a substantially improved penetration todepth. In particular the “I-bottomed V-shaped coils” (also referred toas the Y-shaped coils) are of particular interest, and have been foundto have unexpectedly superior magnetic field profiles for use in TMS.

For example, described herein are Y-shaped Transcranial MagneticStimulation (TMS) electromagnets configured to emit a focused magneticfield. These TMS electromagnets may include: a first bent magnetic coilloop comprising a plurality of windings and a second bent magnetic coilloop comprising a plurality of windings; wherein the first magnetic coilloop comprises a first inner coil region and the second magnetic coilloop comprises a second inner coil region, and wherein the first andsecond inner coil regions are arranged to form a vertex configured sothat the plurality of windings within the first inner coil region for acolumn this is adjacent and parallel to the plurality of windings withinthe second inner coil that are arranged in a column; and wherein thefirst magnetic coil loop comprises a first outer coil region and thesecond magnetic coil loop comprises a second outer coil region, and theangle between the first outer coil region and the second outer coilregion is between about 30 degrees and about 120 degrees.

The first outer coil region may be located opposite the first inner coilregion on the first magnetic coil loop and wherein the second outer coilregion is opposite the second inner coil region on the second magneticcoil loop.

In some variations, the first bent magnetic coil loop comprises greaterthan 5 windings. In some variations, the angle between the first outercoil region and the second outer coil region is approximately 60degrees.

The TMS electromagnet may also include a structural support matrixsurrounding the first and second bent magnetic coil loops.

The first and second bent magnetic coil loops may be electricallyconnected so that the current flows from the first coil loop into thesecond coil loop. Further, the vertex is configured so that current willflow in the same direction in the first and second inner coil regions ofthe vertex.

The first and second bent magnetic coil loops may be arrangedsymmetrically about the vertex. The first and second bent magnetic coilloops may have approximately the same shape and size, or they may bedifferent sizes.

Also described herein are shaped coil Transcranial Magnetic Stimulation(TMS) electromagnet comprising: a first bent magnetic coil loopcomprising a column formed of a plurality of conductive windings; asecond bent magnetic coil loop comprising a column formed of a pluralityof conducive windings; and a vertex region connecting the first andsecond bent magnetic coil loops; wherein the vertex region is formed byaligning the columns of conductive windings within the first bentmagnetic coil loop in parallel with the column of conductive windingswithin the second bent magnetic coil loop; wherein the angle between afirst outer coil region of the first magnetic coil loop and a secondouter coil region of the second magnetic coil loop is less than 120degrees.

The vertex region may comprise an interleaved vertex, as described ingreater detail below, or the vertex region may comprise an I-bottomedvertex (the I-bottomed vertex may be considered a sub-set of theinterleaved vertex).

The first outer coil region may be the region of the coil(s) oppositethe vertex region on the first magnetic coil loop and wherein the secondouter coil region is opposite the vertex region on the second magneticcoil loop.

The first magnetic coil loop may comprise greater than 5 windings.

In some variations the angle between a first outer coil region of thefirst magnetic coil loop and a second outer coil region of the secondmagnetic coil loop is approximately 60 degrees.

As mentioned, the shaped TMS electromagnet my further comprising astructural support matrix surrounding the first and second magnetic coilloops.

The first and second bent magnetic coil loops may be electricallyconnected so that the current flows from the first bent magnetic coilloop into the second bent magnetic coil loop. Further, the vertex may beconfigured so that current will flow in the same direction in theportion of the windings forming the first and second bent magnetic coilloops that are part of the vertex.

Also described herein are shaped coil Transcranial Magnetic Stimulation(TMS) electromagnets comprising: a first bent magnetic coil loopcomprising a plurality of conductive windings; a second bent magneticcoil loop comprising a plurality of conducive windings; and a generallyV-shaped bottom vertex region between the first and second bent magneticcoil loops; wherein the angle between an outer coil region of the firstbent magnetic coil loop and the outer coil region of the second bentmagnetic coil loop is between about 55 and about 65 degrees; and whereinthe V-shaped bottom vertex region is formed by arranging immediatelyadjacent portions of the each coil at an angle of between about 70 andabout 110 degrees relative to each other.

Also described herein are shaped Transcranial Magnetic Stimulation (TMS)electromagnet comprising: a first bent magnetic coil loop formed of acolumn comprising a plurality of windings; a second bent magnetic coilloop formed of a column comprising a plurality of windings; aflat-bottomed vertex region between the first and second bent magneticcoil loops; wherein the angle between an outer coil region of the firstbent magnetic coil loop and the outer coil region of the second bentmagnetic coil loop is between about 55 and about 65 degrees; and whereinthe flat-bottom vertex region is formed by arranging an inner coilregion of the first bent magnetic coil loop immediately adjacent to aninner coil region of the second bent magnetic coil loop so that thecolumn of windings forming the first and second inner coil regions areat an angle of approximately 180 degrees with respect to each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section though a TMS electromagnet having a pair ofcoils oriented in a “Y” configuration, also referred to as an“I-bottomed V-shaped coil pair”.

FIG. 2A shows a partial cross-section through a TMS electromagnet havinga pair of coils oriented in a “U” configuration, also referred to as a“flat-bottomed V-shaped coil pair”.

FIG. 2B is a cross-section through a flat-bottomed V-shaped coil pair(or “U”-shaped coil pair).

FIG. 2C is a cross-section through a V-shaped coil pair.

FIG. 2D is a cross-section through an I-bottomed V-shaped coil pair (or“Y”-shaped coil pair).

FIG. 2E is a cross-section through another V-shaped coil pair having acentral section that is maximized for contact between the centralmembers of the coils.

FIG. 2F is a cross-section through another V-shaped coil pair having acentral section that is maximized for contact between the centralmembers of the coils.

FIG. 3A through 3C show different perspective views of one variation(shown here as a mock-up model) of an I-bottomed V-shaped coil pair.

FIG. 4 is one example of a TMS electromagnet as described herein.

DETAILED DESCRIPTION

In general, the TMS magnets described herein may be referred to asshaped-coil TMS magnets. A shaped-coil TMS magnet typically includes apair of coils (each having multiple windings) that have a non-flat shapeand are connected to each other at a vertex region or point.

A shaped coil may have a bent or curved ring shape. The shaped coilsdescribed herein may also be referred to as “V-shaped” coils.

Prior art TMS magnets having a two coils were typically “flat,” forminga “figure-8” shape. The shaped-coil TMS magnets described hereingenerally have two coils that are at an angle with each other that isless than 180 degrees (an angle of 180 degrees corresponds to thestandard “figure-8” shaped coils), and an angle with respect to ahorizontal plane that is greater than zero (e.g., a standard “figure-8”shaped coil has an angle of 0 degrees with respect to the horizontal).The vertex region, which may also be referred to as the “bottom” of theshaped coil pairs, may be flat (e.g., the coils are connected end-to-endwith a local angle relative to each other of) 180 degrees, parallel(e.g., the coils are connected so that the stack of windings for eachcoil are parallel with the stack of windings of the other coil),V-shaped (e.g., the stack of windings for each coil are angled withrespect to each other), or intermingled/interleaved (e.g., the windingsof each coil overlap with each other). From the vertex region, bothcoils typically extend outwards, subtending an angle that is less than180 degrees. The “angle” of the TMS electromagnet may refer to the angleby which the coils are bent from the horizontal, starting from thestandard figure-8 coil configuration. As illustrated below, the angle ofthe TMS electromagnet may be varied, but in some variations the minimumangle between the outermost portions of the rings is approximately 60degrees.

The two coils are typically in electrical continuity, so that thewindings of one coil are continuous with the windings of the other coil.Coils are typically wound in opposite directions, thus current will flowin opposite directions in each coil. The current though each coil at thevertex region flows in the same direction. The windings of the two coilsare connected through a crossover region, where the windings forming onecoil become continuous with the windings forming the other coil. Thecrossover region may occur at the vertex area (e.g., where the adjacentcoils meet), or may be anywhere else between the coils. The crossoverregion may go from the central turn of one coil to the central turn ofthe other coil.

A coil may be formed of any number of windings. For example, the coilmay be between 8 and 12 windings, between 9 and 11 windings, between 9and 10 windings, etc. In some variations the coils are formed fromcopper flat wire, e.g., 0.984 inch by 0.240 inch wire), though anyappropriate conductor may be used. As mentioned above, the coils forminga TMS electromagnet are typically wound in opposite directions.

As mentioned, the coil typically forms a ring or loop of many adjacentwindings. The stack of windings may form a rectangle when viewed as across-section through the loop.

Thus, a cross-section through a coil may include two side surfaces(which may be the long edges) formed by the edges of all of the windingsin the stack, separated by an outer surface and an inner surface (formedby the outer winding and inner winding, respectively). The side surfacesof the coil are typically curved, forming the bent ring shape of eachcoil.

In many of the examples described herein the pair of coils forming theshape-coil

TMS magnets are symmetric with respect to each other. Thus, they aretypically the same size (including number of windings) and shape.However, in some variations the shapes of the two coils may bedifferent. For example, in some variations the two shaped coils formingthe TMS magnet may be of different sizes. In one variation, one shapedcoil has more windings than the other shaped coil. In some variationsone coil has a different shape than the other coil. For example, in somevariations one coil has a different curvature of bending than the othercoil.

In some variations the coils are generally circular rings formed by thewindings of the conductor. The coil does not necessary have to becircular, but could be oval polyagonal, or the like.

FIG. 1 is a cross-section though one variation of a shaped coil havingan I-bottom configuration. In this variation, the vertex (the connectionbetween the two coils) is formed so that the stacks of windings of eachof the two coils are arranged parallel to each other. Thus, thecross-section appears to roughly form the endpoints of a “Y” shape, withthe bottom portion of the “Y” being the parallel and adjacent windingsof the coils at the vertex (the inner coil region). In FIG. 1, thecross-section through the first outer coil region 110 is part of thesame shaped coil (subcoil A) as the cross-section through the firstinner coil region 111, and the cross-section through the second outercoil region 120 is part of the same shaped coil (subcoil B) as the crosssection through the second inner coil region 121. The cross-section ofthe two inner coil regions 111, 121 are parallel. The maximum angle ofthis variation of shaped coil TMS electromagnet is illustrated 130 asthe angle between the upper margin of subcoil B and the normal (flat)plane.

In this embodiment, this angle is 60 degrees. The maximum angle betweenthe bent wings of the coils is also 60 degrees. The angle at theoutermost edges of the coil from the vertex where the coils meet may bereferred to as the angle of the shaped coil TMS electrode. In FIG. 1,this angle is 60 degrees, both relative to the two coils (the “wings” ofthe coils) and relative to a plane that is perpendicular to the axis ofsymmetry though the vertex. The angle of the shaped coil TMSelectromagnet in some variations may be any value between 15 and 75degrees relative to the perpendicular plane (angle 130 in FIG. 1).Equivalently, the angle between the outermost coil regions of the shapedcoils may be between about 150 degrees and 30 degrees.

The inventors have found that the field emitted by the shaped coil TMSelectromagnet shown in FIG. 1 is generally directed downward, towardsthe target 190, as indicated in FIG. 1. This field is shaped so that ismore focused compared to a comparable “flat” (i.e., figure-8) TMS coil.

FIG. 2A shows another variation of a V-shaped TMS electromagnet. In FIG.2A, the shaped coil TMS electromagnet has a flat bottom, and may bereferred to as a flat bottomed TMS electromagnet (or “flat bottomedV-shaped TMS electromagnet”). In this variation, the first (or “A”)subcoil 201 is adjacent to the second (or “B”) subcoil 202 so that thevertex between the two is a flat region having a zone of mutualinduction 204 where subcoils A and B meet. The direction of electricalcurrent in coils 205 is indicated, illustrating that current flows inopposite directions in the coils (e.g., clockwise/counterclockwise), andis oriented in the same direction at the region where the coils form thevertex 204. In general, the current in the vertex region between the twocoils may travel in the same direction, thereby inducing a consistentmagnetic field.

In the example shown in FIG. 2A, the angle of the shaped coil TMSelectromagnet is approximately 45 degrees relative to the horizontal, asindicated in the cross-sectional schematic shown below the partialsections through the two coils. Thus, the angle between the outer coilregions is approximately 90 degrees. In some variations, the anglebetween the outer coil regions is less than 90 degrees, for example,between about 45 degrees and about 80 degrees (e.g., between about 55degrees and about) 60 degrees. In some variations the angle is greaterthan 90 degrees (e.g., between about 100 degrees and 170 degrees,between about 110 degrees and 160 degrees, between about 120 degrees and150 degrees, etc.).

FIGS. 2B to 2E illustrate various V-shaped TMS electromagnets havingdifferent configurations. Each of these exemplary TMS electromagnets hasa coil angle of 60 degrees, however the arrangement of the vertex isdifferent. For example, FIG. 2B shows a cross-section though anothervariation of a flat-bottomed V-shaped TMS electromagnet. The variationmay be referred to as a generally “U” shaped profile, because of thesubstantially flat bottom of the vertex region. The angles between thecross-sections of the outer coil regions 210, 215 of the two subcoils inthis example is approximately 60 degrees. The angle between thecross-sections of the inner coil regions 211, 216 is 180 degrees (or 0degrees relative to the horizontal plane). Thus, the inner coil regionsof the two coils are arranged so that they are side-by-side, forming theflat bottom.

FIG. 2C shows a cross-section through the TMS electromagnet in which theouter coil regions 220, 225 of each coil are oriented in the samedirection as the cross-section through the inner coil regions 221, 226for each coil. The two coils have an angle between them of 60 degreesrelative both to each other and to the horizontal. Thus, both of thelower regions forming the vertex are angled 60 degrees from thehorizontal. This shape may be similar to the other commerciallyavailable “butterfly” double coils, although oriented opposite thevariation shown here, and may have the same drawbacks inherent in thosemagnets. In particular, such a butterfly coil does not include a centralplanar region where the coils meet (the vertex). This may result in aweaker field, since the each subcoil is wound in a single plane, and thetwo flat plane components are offset by an angle.

FIG. 2D illustrates another variation of an I-bottomed TMSelectromagnet. In this variation, the outer coil regions 230, 235 areboth angled 60 degrees from the horizontal (and relative to each other),but the cross-section through the inner coil regions at the vertex showthat two inner coil regions are parallel (angled 90 degrees with thehorizontal and 0 degrees relative to each other).

FIG. 2E shows an example of a shaped coil TMS electromagnet having aninterleaved bottom region. In this example, the windings forming thebottom region of the vertex are not stacked in a single column, but aresome of them run adjacent to each other for at least part of the regionforming the vertex. The outer coil regions of each coil remain wound ina single (stacked) column). Thus the vertex (bottom or base region ofthe magnet) maximizes the contact between the adjacent windings of eachcoil while minimizing the distance from the coils to the target. Thecoil windings at the inner coil region (in the vertex region) for eachcoil may be arranged to form a flat surface that can abut a similar flatsurface on the adjacent coil. In some variations the coil windingsbetween the two regions 241, 246 may overlap with each other. In FIG.2E, the coil windings of the joined coils 241, 246 forming the vertexare organized so that they have an approximately circular cross-section.The cross-sections 241, 246 of the vertex inner coil regions are shownhaving nine rectangular windings; as mentioned above, other shapes ofwinding material (circular cross-sections, etc.), as well as coilshaving more or fewer windings may be used.

FIG. 2F shows another variation of a shaped coil TMS electromagnet withan interleaved bottom. These regions are referred to as “interleaved”because the windings forming the vertex region for the coils are notstrictly wound in a stacked column, but may overlap or be wound next toeach other, as shown. In FIG. 2F, the vertex region of the TMSelectromagnet has a triangularly shaped cross-section for the coils. InFIG. 2F the vertex is again formed by maximizing the contact between theadjacent coils while minimizing the distance from the coils to thetarget. In the variation shown in FIG. 2F, the coil windings have beenorganized so that they form an approximately triangular cross-section,having a flat surface that faces the target direction. Thecross-sections 251, 256 through the inner coil regions are shown withten rectangular windings, and the outer coil regions 250, 255 are eachat a 60 degree angle with the horizontal in this example. Any of theangles described above may be used for the coils. For example, the wingsof the TMS electromagnet may be separated by between about 60 degreesand about 150 degrees.

FIGS. 3A to 3C illustrate one variation of an I-bottomed (Y-shaped) TMSelectromagnet, similar to the one shown in cross-section in FIG. 1 andFIG. 2D. In FIG. 3A, the two coils forming the TMS electromagnet includea first subcoil 302 (subcoil A) and a second subcoil 301 (subcoil B).The two subcoils meet in a vertex region 305. This central section(vertex) is in a substantially perpendicular orientation with respect tothe target, as illustrated in FIG. 1 by the arrow. The emitted fieldwill be directed towards the target in this direction. The portions ofthe subcoils 301, 302 forming the vertex 305 are substantially parallelin the vertex region, as better seen in FIG. 3B.

The crossover region 303 shown in FIG. 3A-3C extends between the centralloops of the two coils, and is not located in the vertex region,although it could be. These figures also illustrate the connections tothe power source for the coils 310, 311. For example, a TMSelectromagnet may be electrically connected to a power source to providean electrical current that is pulsed with a magnitude of about 5000 A.

Any of the TMS electromagnets described herein may also include asupport structure. FIG. 4 shows one variation of a shaped coil TMSelectromagnet secured to a support structure. The TMS electromagnet inthis example is a Y-shaped shaped coil TMS electromagnet similar tothose described above. This example includes two concentric double(sub)coils of approximately the same diameter windings as a standard 70mm double coil. The inner coil region of each subcoil (of the doublecoil structure) forming the vertex are placed side-by-side vertically,and the outer coil regions of the loops are swept to 60 degrees from thehorizontal plane (with an angle between the outer coil regions of) 60degrees. This variation may be constructed using a single length of flatwire, with no solder at the crossover.

The structural support matrix may completely or partially surround thecoils. The structural support matrix may provide support and protectagainst mechanical shock. Mechanical shock forces may be created inmaking and/or operation of the TMS electromagnet, particularly in thelateral wings, so a structural support matrix (which may be rigid) maybe used. This support structure may be formed of a low electricalconductivity and high thermal conductivity material. In some variations,the support structure may be a hollow strut system that facilitatescooling by air flow/convection, or a solid matrix for heat conduction.The support structure may be filled with a fluid to assist in heattransfer.

In general, the shaped coil TMS electromagnets described herein includetwo coils that are arranged so that the outer portions of each coil(subcoil) are at an angle with respect to the horizontal, and the vertexof the coils, where they are immediately adjacent to each other, may bearranged at a different angle, or to maximize the contact between theloops of the two coils while also maximizing the portion of the coilsnearest the target. For example, in one variation an I-bottomed V-shapedTMS electromagnet is configured so that the outer portions of each coilare at an angle of 60 degrees with respect to the horizontal (alsoforming an angle of 60 degrees between them), while the vertex region ofthe TMS electromagnet is formed by placing the coils regions parallel toeach other, so that the vertex region of each coil forms an angle of 90degrees with the horizontal. In all of these cases the “horizontal”direction will correspond to the plane of the target. The horizontaldirection is also perpendicular to the axes of symmetry for the coils.

In some variations the TMS electromagnets described herein may bedefined by the angles formed by the outer portion of the coils withhorizontal and the angles formed by the inner or vertex portions of thecoil with the horizontal. The angle formed by the outer portion of thecoils may be around about 60 degrees (e.g., between about 50 and about70 degrees, between about 45 and about 75 degrees, between about 55 andabout 65 degrees, etc.) The angle formed by the inner or vertex portionmay be any angle between 0 and 90 degrees. In particular, the angle maybe 90 degrees. In still other variations, the loops of the coils formingthe vertex are arranged to maximize the contact between loops ofadjacent coils. For example, the coils may be arranged so that the loopsof each coil in the vertex region form a semicircle that combine to forma circle. In one variation, the coils may be arranged so that the loopsof each coil in the vertex region form a right triangle which matches upwith the adjacent coil to form a triangle. FIG. 2F illustrates onevariation of this coil arrangement.

The various embodiments described above are provided by way ofillustration only and should not be construed to limit the invention.Based on the above discussion and illustrations, those skilled in theart will readily recognize that various modifications and changes may bemade to the present invention without strictly following the exemplaryembodiments and applications illustrated and described herein. Suchmodifications and changes do not depart from the true spirit and scopeof the present invention, which is set forth in the following claims.

What is claimed is:
 1. A Transcranial Magnetic Stimulation (TMS)electromagnet comprising: a first bent magnetic coil loop formed of acolumn comprising a plurality of windings; a second bent magnetic coilloop formed of a column comprising a plurality of windings; aflat-bottomed vertex region between the first and second bent magneticcoil loops; wherein the angle between an outer coil region of the firstbent magnetic coil loop and the outer coil region of the second bentmagnetic coil loop is between about 55 and about 65 degrees; and whereinthe flat-bottom vertex region is formed by arranging an inner coilregion of the first bent magnetic coil loop immediately adjacent to aninner coil region of the second bent magnetic coil loop so that thecolumn of windings forming the first and second inner coil regions areat an angle of approximately 180 degrees with respect to each other. 2.The TMS electromagnetic of claim 1, wherein each of the first and secondbent magnetic coil loops comprises greater than 5 windings.
 3. The TMSelectromagnet of claim 1, further comprising a structural support matrixsurrounding the first and second bent magnetic coil loops.
 4. The TMSelectromagnet of claim 1, wherein the first and second bent magneticcoil loops are electrically connected so that the current flows from thefirst bent magnetic coil loop into the second bent magnetic coil loop.5. The TMS electromagnet of claim 1, wherein the vertex is configured sothat current will flow in the same direction in the first and secondinner coil regions of the vertex.
 6. The TMS electromagnet of claim 1,wherein the first and second bent magnetic coil loops are arrangedsymmetrically about the vertex.
 7. The TMS electromagnet of claim 1,wherein the first and second bent magnetic coil loops have approximatelythe same shape and size.
 8. A Transcranial Magnetic Stimulation (TMS)electromagnet comprising: a first bent magnetic coil loop comprising aplurality of conductive windings; a second bent magnetic coil loopcomprising a plurality of conducive windings; and a generally V-shapedbottom vertex region between an inner coil region of the first bentmagnetic coil loop and an inner coil region of the second bent magneticcoil loop; wherein the angle between an outer coil region of the firstbent magnetic coil loop and the outer coil region of the second bentmagnetic coil loop is between about 55 and about 65 degrees; and whereinthe V-shaped bottom vertex region is formed by arranging an inner coilregion of the first magnetic coil loop immediately adjacent to an innercoil region of the second magnetic loop so that the column of windingsforming the first and second inner coil regions are substantiallyparallel.
 9. The TMS electromagnetic of claim 8, wherein each of thefirst and second bent magnetic coil loops comprises greater than 5windings.
 10. The TMS electromagnet of claim 8, further comprising astructural support matrix surrounding the first and second bent magneticcoil loops.
 11. The TMS electromagnet of claim 8, wherein the first andsecond bent magnetic coil loops are electrically connected so that thecurrent flows from the first bent magnetic coil loop into the secondbent magnetic coil loop.
 12. The TMS electromagnet of claim 8, whereinthe vertex is configured so that current will flow in the same directionin the first and second inner coil regions of the vertex.
 13. The TMSelectromagnet of claim 8, wherein the first and second bent magneticcoil loops are arranged symmetrically about the vertex.
 14. The TMSelectromagnet of claim 8, wherein the first and second bent magneticcoil loops have approximately the same shape and size.